1. Field of the Invention
This invention relates generally to means and method for setting up and applying a plastic film sheet or strip, one side of which has a pressure sensitive adhesive coating, to a suitable display surface and more particularly to a tool for removing the protective backing from a section of said film containing informative material and prepositioning it prior to the film being affixed to an architectural or engineering drawing, a tracing, an artwork, a sign, a poster, or the like.
2. Description of the Prior Art
During the preparation of architectural and engineering drawings, it has become common practice to type or otherwise imprint information which is supplemental to the main subject matter of a drawing on separate sheets or strips of transparent plastic film suitably pre-coated with adhesive for attachment to the drawing. Typically, this supplemental material includes general specifications, equipment schedules and the like which are time-consuming and expensive to hand letter. The drawings themselves, commonly referred to as "master drawings" and measuring 22.times.34 inches more or less, are too large to be typed on directly in a conventional typewriter without creasing. While preparing master drawings with the use of such film has eliminated much of the expense and time formerly required for hand lettering, the methods and devices used or proposed for use for accomplishing the tasks of removing the backing protecting the adhesive coated surface of such a film prior to its use and then applying it to a master drawing have been far from satisfactory.
Up to the present, stripping the protective backing from sheets or tape has been initiated with the insertion of a long fingernail or of a knife edge beneath the backing near a corner thereof. Wielding a knife edge in such an operation can, of course, be both hazardous to a user and damaging to the film which one wishes to affix. Once separation is successfully started, the user must remove the backing from the film while simultaneously stretching it between the index finger and the thumb of both hands, a procedure requiring three hands. Otherwise, the electrostatic charge generated when the backing is separated will cause the film to cling to any convenient object and may bring an adhesive coated section of the film into premature contact with a nearby surface.
Once the backing is separated, the user has had only two options: either to affix the film directly to the master drawing itself or to a transfer device. In a direct application, considerable difficulty is experienced in lowering the film to the surface of the master drawing with any degree of precision in alignment and simultaneously extricating one's fingers. Moreover, an electrostatic charge on the film makes last second readjustments in alignment impractical as the film, its adhesive coated surface exposed to the master drawing, approaches it. Attaching a portion of the adhesive coated side of the film to the previously removed backing, recycled to serve as a transfer device, is an alternate method practised by some but is awkward and time-consuming to accomplish.